1. Field of the Invention
The present invention relates to medical procedures and instruments, and more particularly to apparatus and methods for dissection of tissue from skin to an underlying blood vessel or body structure, and the methods of accomplishing such dissections and arterial and venous punctures.
2. Description of the Prior Art
Present surgical practice for percutaneous puncture of the femoral artery with entry into the arterial lumen is a blind approach. The same is true for other arteries and veins accessible via the skin. These procedures have become ever more common and are frequent during procedures relating to invasive cardiology, invasive radiology, and cardiac surgery.
Currently, puncture of a femoral artery is accomplished by first feeling the pulse through the skin and underlying tissue; a trajectory or path for the needle is thereby estimated by the practitioner to properly engage the artery. The needle is then advanced toward the artery through the skin, and it is hoped that the needle will puncture the artery in its mid-line, which is optimal. However, often the needle will puncture the artery in an off-center position, or the artery may be missed entirely, and multiple attempts executed before success. Further, if the artery is punctured off-center this is not evident. Thus, in general, the quality of the puncture is not known.
An off-center puncture makes insertion of the catheter more difficult and increases the likelihood of arterial trauma and tearing of the vessel wall, resulting in more difficult hemostasis at the end of the procedure. Many factors interfere with a successful mid-line puncture, leading to an off-center puncture or missing the artery entirely. Subcutaneous tissue, particularly if fibrous, may deflect the needle from its intended path. Thicker subcutaneous tissue, as found in obese persons, increases the difficulty of accurately assuming the trajectory of the needle and resulting puncture of the artery, as well as depriving the operator of feeling that the puncture is actually occurring. Additionally, it must be estimated as to when the needle has actually entered the artery. Hence, many operators may push the needle through the rear wall without realizing that this has occurred.
Because of the uncertainty as to the location of the intersection of the needle with the artery and entry of the needle tip into the true lumen of the artery, many operators will intentionally push the needle to a greater depth so that the rear wall is also punctured (double-wall puncture), and then withdraw the needle slowly while awaiting the pulse of blood through the needle's open channel to indicate that the tip of the needle now lies inside the arterial lumen.
The difficulties enumerated above with respect to percutaneous vascular puncture are exacerbated when attempting a venous puncture, since pronounced pulsations to define the vessel are absent, and venous walls are thinner, hence more easily damaged. Also, venous entry (e.g. jugular, subclavian) relies heavily on superficial anatomic landmarks, which are less precise.
Percutaneous entry of a blood vessel is facilitated by instruments or apparatus that dissect a channel or path from skin to vessel, thereby eliminating tissue resistance to guidewires, catheters, or other implements. The geometry of contemporary instruments is such that the handles of the instrument, as held by the operator, and the joint of the instrument obstruct and prevent a clear view of the tips and the pathway they are creating.
It is important that a dissecting instrument provide a clear, unobstructed view of the dissecting tips and the channel created therefrom. For a dissecting instrument to provide such visualization of the subcutaneous channel and the underlying blood vessel, the gripping handles must be offset from the dissecting blades or fingers in such a way as to provide a direct and clear line of sight down to the tips of the instrument and hence an unobstructed view of the surgical site. Additionally, the channel created by the fingers must be broad enough for visualization to occur.
Another problem associated with percutaneous entry into a blood vessel is the bleeding that results. After the needle is removed and/or any other invasive removed from the blood vessel, it is necessary to close the general area of the entry on the vessel. This, however, is not a completely successful method of preventing the bleeding. Since the pressure is applied externally on a relatively large area, there is always seepage resulting in bruising or even the buildup of adhesions from the internal blood.
Numerous surgical implements have been developed which would be useful in connection with the procedures to be accomplished by the present invention. However, none of these tools show or disclose configurations which meet the requirements for the procedures as set forth in the present invention. Some of the prior patents dealing with this subject matter are as follows.
U.S. Pat. No. 5,797,939 to Yoon discloses an endoscopic scissor. Note that the finger loops of the handle are at an angle to the main shaft, and that they are spread when the cutting blades are open, and also spread when the cutting blades are closed. (See FIG. 3). Additionally, the cylindrical tubular section of the device allows for passage of accessories to the end of the blades.
U.S. Pat. No. 5,356,408 to Rydell discloses a bipolar electrosurgical scissor instrument in which the handles are offset at 90 degrees and remain in an apparently open position when the blade itself is closed. Additionally, the blades are bent at an angle to the linear axis of the device to provide for an unobstructed view of the cutting area.
U.S. Pat. No. 5,153,997 to Chiavaras et al. discloses ergonomic scissors in which the finger grips are at right angles to the blade.
U.S. Pat. No. 4,889,112 to Schachner et al discloses a tracheostomy enlarging tool, which has offset probing fingers 107 and 108. These fingers have passage means in them to surround a wire which has been inserted into the trachea to guide the fingers into the trachea so that the passage into the trachea can be enlarged to widen the opening.
U.S. Pat. No. 4,819,636 to Gerich et al discloses a device for cutting and squeezing tubing, in which the finger mounts and the handles are offset from the cutting blades or working arms of the instrument.
U.S. Pat. No. 4,140,124 to Curutchet discloses a surgical instrument having an offset handle with special means for holding the thumb and the fingers in a ergonomic position. This patent does not have the same orientation of the handles as does the present invention.
U.S. Pat. No. 4,049,002 to Kletschka et al. discloses various scissors or clamps having fluid passages in the handles to allow fluid to be directed towards the tip of the implement. However, note that the passages are internal and are not used to coact with each other to form a cylindrical pathway between the blades.
U.S. Pat. No. 3,987,542 to Visco discloses scissors with off-set handles. Additionally, although not for the same purpose, the blades of the scissors have tubular sections. These are more for strength than for any functional purpose.
U.S. Pat. No. 1,214,562 to McGrath discloses lawn power sheers, which has off-set blades to the body portions 14 of the levers.
U.S. Pat. No. 331,179 DES to Omichi discloses hair-cutting scissors with a curved blade.
U.S. Pat. No. 310,714 DES to Dolwick discloses a surgical or dental scissors having the finger loops bent at an angle from the main shaft of the device and having the blade portions bent similarly to form another angle so as to make the device a double curved instrument with the handles somewhat parallel to the blades and the main shaft at an angle to both.
U.S. Pat. No. 258,714 DES to Backstrom discloses nail scissors having curved cutting blades.
U.S. Pat. No. 239,910 to Megna discloses scissors having bent finger loops.
U.S. Pat. No. 231,034 DES to Moore discloses a surgical clamp with bent fingers.
U.S. Pat. No. 2,191 to Pitney discloses a speculum having fingers AA which coact with the handle BB for spreading. FIG. 2 shows a levator, which is used to examine the anus once the fingers AA of the speculum are inserted.